A constitution disclosed in, for example, Patent Document 1 is known as such a type of vibration-damping device. Such a vibration-damping device includes a first tubular attachment member joined to one of a vibration generating unit and a vibration receiving unit, a second attachment member joined to the other of the vibration generating unit and the vibration receiving unit, an elastic body coupling the attachment members to each other, and partition members configured to partition a liquid chamber in the first attachment member in which a liquid is sealed into a first liquid chamber and a second liquid chamber. The vibration-damping device includes a first restricting passage and a second restricting passage through which the first liquid chamber and second liquid chambers communicate with each other, a cylinder chamber provided between the first liquid chamber and the second liquid chamber, and a plunger member arranged movably between an open position and a closed position in the cylinder chamber.
A plurality of types of vibrations with different frequencies such as, for example, idle vibrations and shake vibrations are input to the vibration-damping device. For this reason, resonance frequencies of the first restriction passage and the second restriction passage are set (tuned) to frequencies of the different types of vibrations in the vibration-damping device. The plunger member is moved between the open position and the closed position in accordance with frequencies of the input vibrations so that a restriction passage through which the liquid flows is switched between the first restriction passage and the second restriction passage.